Range-wide population genomics of the spongy moth, Lymantria dispar (Erebidae): Implications for biosurveillance, subspecies classification and phylogeography of a destructive moth

The spongy moth, Lymantria dispar, is an irruptive forest pest native to Eurasia where its range extends from coast to coast and overspills into northern Africa. Accidentally introduced from Europe in Massachusetts in 1868–69, it is now established in North America where it is considered a highly destructive invasive pest. A fine-scale characterization of its population genetic structure would facilitate identification of source populations for specimens intercepted during ship inspections in North America and would enable mapping of introduction pathways to help prevent future incursions into novel environments. In addition, detailed knowledge of L. dispar’s global population structure would provide new insight into the adequacy of its current subspecies classification system and its phylogeographic history. To address these issues, we generated >2,000 genotyping-by-sequencing-derived SNPs from 1,445 contemporary specimens sampled at 65 locations in 25 countries/3 continents. Using ..., Moth sampling
The bulk of spongy moth specimens were collected during the summers of 2017 and 2018, using milk-carton type pheromone-baited traps. Additional samples (whole moths or parts thereof) from regions not fully covered by our network of traps were provided by colleagues who had collected them in the context of independent studies; with the exception of a few samples, collection dates for these were recent (overall, 93% of the moths used were collected between 2013 and 2018, and most specimens were males [only 0.8% of females])
DNA extraction and sequencing
For DNA extraction, we sampled one antenna and three legs from each moth. These were frozen in liquid nitrogen and ground using a Retsch MM 200 mixer mill (Retsch technology, Haan, Germany). Then, DNA was extracted with the DNeasy 96 Blood & Tissue Kit (Qiagen, Carlsbad, CA, USA) following the manufacturer's instructions, with the exception of an additional RNase A treatment before the addition of buffer AL/ethanol (4 µL..., The different filtering procedures were carried out using VCFtools v0.1.16 (Danecek et al., 2011), and the resulting VCF file was converted to file formats suitable for each subsequent analysis using PGDSpider v2.1.1.5 (Lischer & Excoffier, 2012).

Danecek, P., Auton, A., Abecasis, G., Albers, C.A., Banks, E., DePristo, M.A., Handsaker, R.E., Lunter, G., Marth, G.T., Sherry, S.T., McVean, G., Durbin, R., & 1000 Genomes Project Analysis Group. (2011). The variant call format and VCFtools. Bioinformatics, 27(15), 2156‑2158. DOI: 10.1093/bioinformatics/btr330
Lischer, H.E.L., & Excoffier, L. (2012). PGDSpider : An automated data conversion tool for connecting population genetics and genomics programs. Bioinformatics, 28(2), 298‑299. DOI: 10.1093/bioinformatics/btr642